The invention relates to a device for sterilizing and filtering water flowing through a sanitary appliance, having
a) a housing, which comprises an inlet and an outlet for the water;
b) a filtering apparatus, which is disposed in a treatment chamber inside the housing and subdivides the treatment chamber into at least two sub-chambers and through which the water travelling between the inlet and the outlet of the housing has to pass;
c) a UV lamp, which is disposed inside the housing and the radiation of which is directed towards the water flowing through and towards the filtering apparatus.
In recent years the dangers arising in the field of sanitation from water contaminated with micro-organisms, in particular bacteria, amoebae or other monocellular organisms, have become ever clearer. For said reason, increased importance is being attached to water sterilization. In said connection, there have been reports of experiments to sterilize flowing water through exposure to UV light, which is of a wavelength suitable for killing micro-organisms carried along in the water. To extend the retention time of said micro-organisms in the region of the UV lamp, use was made of filtering apparatuses, by which the micro-organisms were retained. Said filtering apparatuses subdivided the treatment chamber into only two sub-chambers, of which the one was connected to the inlet of the device, the other to the outlet of the device. This produced a relatively small effective surface of the filtering apparatus, resulting not only in a relatively low throughput of water but also in a relatively short useful life of the filtering apparatus.
U.S. Pat. No. 5,540,848 A describes a water sterilizing device disposed in a canister and having a UV lamp, around which water which is to be sterilized flows. In the process, the water also passes through a filter body of the type described above, which in a sleeve-like manner surrounds a part of the UV lamp.
In the water sterilizing device designed for a swimming pool according to EP 0 531 817 A, a series of different purifying devices are provided. In a disinfecting device, water is sterilized through irradiation by a UV lamp. Provided as a filtering device is i.a. a device having a plurality of filters, which in turn are subdivided into a plurality of sub-chambers and disposed in a housing. In one embodiment, the UV lamp lies inside a concentric arrangement of filters, wherein the outer-lying filter comprises a ceramic filter body.
Said known devices are disposed upstream of the actual water removal points (dispensing points). Here, there is always still the risk of germs collecting in the water channel from the sterilizing device to the dispensing point. Sterilization of said water channel is not possible by means of the known sterilizing devices.
The object of the present invention is therefore to refine a device of the type described initially in such a way that reliable sterilization of the water at the water removal point is guaranteed.
Said object is achieved according to the invention in that
d) the housing is so dimensioned that the device is insertable into the water channel of a sanitary appliance;
e) the filtering apparatus is a sintered body which transmits UV radiation;
f) the sub-chambers of the treatment chamber are subdivided into two sets, of which at least one comprises a plurality of sub-chambers;
g) the sub-chambers of the one set communicate with the inlet of the housing and the sub-chambers of the other set communicate with the outlet of the housing, wherein
h) the sub-chambers of the one set are separated from the sub-chambers of the other set by active filter regions of the filtering apparatus.
The dimensioning of the water sterilizing device such that the latter may be installed in a sanitary appliance guarantees reliable sterilization of the water up to the removal point, with the result that the removed water is reliably sterilized.
The required compact nature of the device means that the purifying components have to be fashioned in such a way that, given a small overall design, the throughput is increased and the service life of the filtering apparatus extended. According to the invention, therefore, a plurality of sub-chambers are used at the inlet side and/or the outlet side of the filtering apparatus. Said plurality of sub-chambers increases the effective surface of the filtering apparatus, thereby enabling a greater throughput. What is more, the filtering apparatus with a larger active filter surface may pick up more impurities before it is exhausted and has to be exchanged.
Designing the filtering apparatus as a sintered body, which transmits UV radiation, guarantees on the one hand an efficient filtering action and on the other hand a sterilizing effect by the UV radiation also inside the filtering apparatus.
When the sub-chambers of at least one of the two sets extend along a lateral surface of the filtering apparatus, manufacture of the filtering apparatus is particularly easy: all that is necessary is to provide a suitable surface contour which, for example, takes the form of paraxial channels or grooves in the lateral surface of the filtering apparatus.
Given said design principle, there are again two distinct preferred variants. Either the sub-chambers of at least one set are formed between the outer lateral surface of the filtering apparatus and the inner surface of the housing: manufacture of the filtering apparatus is then particularly easy because the requisite channels or grooves may easily be introduced in the outer lateral surface. Or the sub-chambers of at least one set are formed between an inner lateral surface of the filtering apparatus and the luminous element of the UV lamp: it is then guaranteed that the water flowing through said sub-chambers is always reached by the UV rays, even when the filter is extremely clogged.
The sub-chambers of at least one set may alternatively take the form of through-bores of the filtering apparatus. This automatically satisfies the requirement of the sub-chambers that active filter material has to be passed through along the path between the sub-chambers of the one set and the sub-chambers of the other set.
Particularly preferred is the refinement of the invention, in which the sub-chambers are delimited at opposite ends in each case by an intermediate plate, wherein each intermediate plate has through-openings, which communicate with one of the two sets of sub-chambers. It is then namely possible for the geometric contours of the filtering apparatus, which delimit the sub-chambers at one side, to be made constant over the entire filtering apparatus in axial direction. The assignment of the sub-chambers to the two sets is effected in a simple manner by means of the two intermediate plates, which in each case close one of the two sets of sub-chambers and connect the other set of sub-chambers either to the inlet or to the outlet of the device.